Polyvinylamine crosslinked polymer particles have been proposed for a wide range of usage, such as gas adsorbents and anion exchange resins. As an example method for producing polyvinylamine crosslinked polymer particles, there has been proposed a method for obtaining a polyvinylamine crosslinked product, for example, by copolymerization of N-vinylformamide (hereinafter abbreviated as NVF) and divinylbenzene or a (meth)acrylate- or (meth)acrylamide-based crosslinkable monomer and subsequent hydrolysis of the formamide group of the obtained crosslinked polymer to provide an amino group (Patent Literature 1). In this method, however, the polymer needs to be dried and pulverized after the polymerization is complete, and the various forms of the product are obtained. There has also been disclosed a method of reverse-phase suspension polymerization of NVF and divinylbenzene in cyclohexane while stirring (Patent Literature 2). In this method, crosslinked polymer particles are normally obtained. However, after polymerization, cyclohexane as polymerization medium, needs to be removed, which requires an operation such as evaporation. In addition, a problem associated with residual cyclohexane and the like arises because it is difficult to completely remove cyclohexane and the like.
Patent Literature 1: Japanese Patent Application Laid-Open No. Sho. 61-51007
Patent Literature 2: Japanese Patent Application Laid-Open No. Hei. 6-190235